Enhancement of the E(J, B) Power Law Characterization for Superconducting Wires from Electrical Measurements on a Coil

We propose an original method for the characterization of superconducting tapes and wires from electrical measurements on a test coil. The principle is to measure the voltage-current characteristic of a coil for several values of the external applied flux density. A computer program then allows finding parameters of a model of the E(J, B) law that best fit the experimental curves. A numerical study on the algorithm convergence and on the accuracy of results was performed. This method has been employed experimentally to characterize a BiSCCO tape. Parameters of three different models have been obtained and compared. This process has several advantages compared to the conventional measurements on short samples: the voltage to noise ratio is higher and the self flux density of the coil is taken into account. Two models that fits well experimental curves were found.